No, it should never change.  If it changes, then it's a runtime value, and that hurts performance.

In that case, what should it be?  16 on 32-bit is a given, what about 64-bit?

-Steve



----- Original Message ----
> From: Sean Kelly <sean at invisibleduck.org>
> To: Discuss the phobos library for D <phobos at puremagic.com>
> Sent: Tue, June 29, 2010 12:48:39 PM
> Subject: Re: [phobos] byte alignment for arrays
> 
> I think it should be enough just to make it a documented requirement for allocators.  It's not like it will ever change, right?

On Jun 28,
> 2010, at 2:07 PM, Steve Schveighoffer wrote:

> All,
> 
> 
> Should there be something in the runtime that defines the minimum align size for things like memory blocks?  That might make this easier to deal with from a design perspective...
> 
> ----- Original Message ----
>> 
> From: Jason Spencer <
> href="mailto:spencer8 at sbcglobal.net">spencer8 at sbcglobal.net>
>> 
> 
>> Hmmm.  The natural thing would be to have some type to
> describe these
>> 128-bit values (akin to __m128 in gcc, Intel and MS
> compilers) and use sizeof on
>> that.  I don't see that D has any
> MMX/SSE intrinsics, so I don't know if
>> there is a standard
> type.  If you don't have such a thing defined by the
>> compiler,
> I'd be tempted to define it, based on which version of the compiler
>> 
> will compile this code (i.e. 32- or 64-bit dmd).  Then you can use that in
> 
>> your sizeof.  Maybe you'll get lucky, and that will become
> standard
>> :)
> 
> 
> 
> 
> 
> _______________________________________________
> phobos mailing
> list
> 
> href="mailto:phobos at puremagic.com">phobos at puremagic.com
> 
> http://lists.puremagic.com/mailman/listinfo/phobos

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16, I believe.  I haven't heard of a larger min size being required.

On Jun 29, 2010, at 10:24 AM, Steve Schveighoffer wrote:

> No, it should never change.  If it changes, then it's a runtime value, and that hurts performance.
> 
> In that case, what should it be?  16 on 32-bit is a given, what about 64-bit?
> 
> -Steve
> 
> 
> 
> ----- Original Message ----
>> From: Sean Kelly <sean at invisibleduck.org>
>> To: Discuss the phobos library for D <phobos at puremagic.com>
>> Sent: Tue, June 29, 2010 12:48:39 PM
>> Subject: Re: [phobos] byte alignment for arrays
>> 
>> I think it should be enough just to make it a documented requirement for allocators.  It's not like it will ever change, right?
> 
> On Jun 28,
>> 2010, at 2:07 PM, Steve Schveighoffer wrote:
> 
>> All,
>> 
>> 
>> Should there be something in the runtime that defines the minimum align size for things like memory blocks?  That might make this easier to deal with from a design perspective...
>> 
>> ----- Original Message ----
>>> 
>> From: Jason Spencer <
>> href="mailto:spencer8 at sbcglobal.net">spencer8 at sbcglobal.net>
>>> 
>> 
>>> Hmmm.  The natural thing would be to have some type to
>> describe these
>>> 128-bit values (akin to __m128 in gcc, Intel and MS
>> compilers) and use sizeof on
>>> that.  I don't see that D has any
>> MMX/SSE intrinsics, so I don't know if
>>> there is a standard
>> type.  If you don't have such a thing defined by the
>>> compiler,
>> I'd be tempted to define it, based on which version of the compiler
>>> 
>> will compile this code (i.e. 32- or 64-bit dmd).  Then you can use that in
>> 
>>> your sizeof.  Maybe you'll get lucky, and that will become
>> standard
>>> :)
>> 
>> 
>> 
>> 
>> 
>> _______________________________________________
>> phobos mailing
>> list
>> 
>> href="mailto:phobos at puremagic.com">phobos at puremagic.com
>> 
>> http://lists.puremagic.com/mailman/listinfo/phobos
> 
> _______________________________________________
> phobos
>> mailing list
> 
>> href="mailto:phobos at puremagic.com">phobos at puremagic.com
> 
>> href="http://lists.puremagic.com/mailman/listinfo/phobos" target=_blank
>>> http://lists.puremagic.com/mailman/listinfo/phobos
> 
> 
> 
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